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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 22, Issue 12 - Dec 2005
Volume 22, Issue 11 - Nov 2005
Volume 22, Issue 10 - Oct 2005
Volume 22, Issue 9 - Sep 2005
Volume 22, Issue 8 - Aug 2005
Volume 22, Issue 7 - Jul 2005
Volume 22, Issue 6 - Jun 2005
Volume 22, Issue 5 - May 2005
Volume 22, Issue 4 - Apr 2005
Volume 22, Issue 3 - Mar 2005
Volume 22, Issue 2 - Feb 2005
Volume 22, Issue 1 - Jan 2005
Selecting the target year
Sensor Technology for Digital Radiography
Kim, Ho-Kyung ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 7~16
Dissimilar Metal Welding of Austenite Stainless Steel and Low Carbon Steel using CW Nd:YAG Laser
Yoo Young Tae ; Shin Ho Jun ; Ahn Dong-Gyu ; Im Kiegon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 17~26
Dissimilar-metal welds(DHWs) are used widely in various industrial applications due to the pratical importance from the technical and economic aspect. However, DMWs have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMWs have used the various of heat source to decrease such as faults. In this paper, the weldability on dissimilar metal welds of Austenite stainless steel and Low carbon steel using a continuous wave Nd:YAG laser was experimentally investigated. Experiments were conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser
The Effect of Pad Groove Density on CMP Characteristics
Park Kihyun ; Jung Jaewoo ; Lee Hyunseop ; Seo Heondeok ; Jeong Seokhun ; Lee Sangjik ; Jeong Haedo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 27~33
Polishing pads play an important role in chemical mechanical polishing(CMP) which has recently been recognized at the most effective method to achieve global planarization. In this paper, we have investigated CMP characteristics as a change of groove density of polishing pads. The parameter
is proposed to estimate groove density of pad. The
is defined as groove area divided by pitch area. As the groove density value increased, removal rate increased to some point and then gradually saturated in case of increasing the groove density excessively. In addition Within wafer non-uniformity(WIWNU) worse as groove density increased excessively, although WIWNU improved as groove density increased. Also the uniformity of temperature of pad surface decreased as the groove density increased. It was because that the cooling effect increased as groove density increased. In other words, increasing the groove density which means the apparent contact area of pad has influence on amount of discharge of slurry during polishing process.
A Learning Method of LQR Controller Using Jacobian
Lim, Yoon-Kyu ; Chung, Byeong-Mook ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 34~41
Generally, it is not easy to get a suitable controller for multi variable systems. If the modeling equation of the system can be found, it is possible to get LQR control as an optimal solution. This paper suggests an LQR learning method to design LQR controller without the modeling equation. The proposed algorithm uses the same cost function with error and input energy as LQR is used, and the LQR controller is trained to reduce the function. In this training process, the Jacobian matrix that informs the converging direction of the controller Is used. Jacobian means the relationship of output variations for input variations and can be approximately found by the simple experiments. In the simulations of a hydrofoil catamaran with multi variables, it can be confirmed that the training of LQR controller is possible by using the approximate Jacobian matrix instead of the modeling equation and this controller is not worse than the traditional LQR controller.
Modeling of a Non-contact Type Precision Magnetic Displacement Sensor
Shin, Woo-Cheol ; Hong, Jun-Hee ; Lee, Kee-Seok ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 42~49
Our purpose is to develop a precision magnetic displacement sensor that has sub-micron resolution and small size probe. To achieve this, we first have tried to establish mathematical models of a magnetic sensor in this paper. The inductance model that presents basic measuring principle of a magnetic sensor is based on equivalent magnetic circuit method. Especially we have concentrated on modeling of magnetic flux leakage and magnetic flux fringing. The induced model is verified by experimental results. The model, including the magnetic flux leakage and flux fringing effects, is in good agreement with the experimental data. Subsequently, based on the augmented model, we will design magnetic sensor probe in order to obtain high performances and to scale down the probe.
Development of Optical Fiber Displacement Sensor for Non-contact Vibration Measurement in the High Speed Rotation System
Lee, Kee-Seok ; Hong, Jun-Hee ; Shin, Woo-Cheol ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 50~56
This paper is described a development of an optical fiber displacement sensor. The optical fiber sensor using an intensity modulated measures the displacement between target and sensor. A prototype sensor is composed of a transmitting part, a receiving part and a signal processing circuit. The experiment was conducted not only the sensor performance but also factors that affect intensity. The main performance of this sensor is resolution of 0.37um and the non-linearity
FS and the dynamic bandwidth of about 6.3kHz. As a result of rotation test, the prototype sensor showed an equivalent performance to a commercial eddy current sensor.
Influence of Dither Motion on the Friction Coefficient of a Capsule-type Endoscope
Hong Yeh-Sun ; Choi Il-Soo ; Kim Byung-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 57~63
Development of a locomotive mechanism fer the capsule type endoscopes will largely enhance the ability to diagnose disease of digestive organs. In connection with it, most of researches have focused on an installable locomotive mechanism in the capsule. In this paper, it is introduced that the movement of a capsule type endoscope in digestive organ can be manipulated by magnetic force produced outside human body. Since the magnetic force is provided by permanent magnets, no additional power supply to the capsule is required. Using a robotic manipulator for locating the external magnet, the capsule motion control system can cover the whole human digestive organs. This study is particularly concentrated on dither motion effect to improve the mobility of capsule type endoscope. It was experimentally found out that the friction coefficient between the capsule and digestive organ can be remarkably reduced by superposing yawing or rolling dither motion on the translatory motion. In this paper, the experimental results obtained with the direction, amplitude and frequency of sinusoidal dither motion changed is reported.
A Study on Pressure Control of Pneumatic Regulator using Modified PWM Algorithm
Kim HyoungSeog ; Ahn KyoungKwan ; Lee ByungRyong ; Yun SoNam ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 64~70
The development of an accurate and energy saving pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation(MPWM) valve pulsing algorithm allows the pneumatic regulator to become energy saying system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM(MPWM) algorithm shows that control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm are demonstrated through experiments with various reference trajectories.
A study on the Development of Automatic Bottle Air Rinser
Kim, Dae-Sung ; Kim, Hyun-Jin ; Lee, Choon-Man ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 71~75
This study has been focused on the development of automatic bottle air rinser. It is designed to rinse clean empty bottles prior to filling. The bottles are automatically indexed beneath an air nozzle that has both a clean airjet and vacuum source. The bottle is first given a burst of clean air to loosen any particles from the wall of the bottle. A vacuum sequence follows which removes all particulates into a self contained filter unit. In order to the provide the desired function, analysis is carried out by FEM simulation using FLUENT and CATIA software. The final results of analysis are applied to the design of automatic bottle rinser and the machine is successfully developed.
An Investigation on the Computing Offsets of Free form Curve using the Biarc Approximation Method
Yoo Dong-Jin ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 76~83
In this study a general method for computing offsets of free form curves is presented. In the method arbitrary free form curve is approximated with point series considering required tolerance. The point series are offset precisely using the normal vectors computed at each point and loop removal is carried out by the newly suggested algorithm. The resulting offset points are transformed to lines and arcs using the biarc approximation method. Tangent vectors for approximation of discrete points data are calculated by traditional local interpolation scheme. In order to show the validity and generality of the proposed method , various of offsettings are carried our for the base curves with complex shapes.
The Study of Microstructure Influence at Fretting Contacts using Crystal Plasticity Simulation
Ko, Jun-Bin ; Goh, Chung-Hyun ; Lee, Kee-Seok ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 84~91
The role of microstructure is quite significant in fretting of Ti-6Al-4V since its material properties depend strongly on crystallographic texture. In this study, we adopt crystal plasticity theory with a 2-D planar triple slip idealization to account fur microstructure effects such as grain orientation distribution, grain geometry, as well as
colony size. Crystal plasticity simulations suggest strong implications of microstructure effects at fretting contacts.
A Study on the Dynamic Material's Characteristics of Tungsten Alloy using Split Hopkinson Pressure Bar
Hwang, Doo-Soon ; Rho, Beong-Lae ; Hong, Sung-In ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 92~99
Tungsten heavy metal is characterized by a high density and novel combination of strength and ductility. Among them, 90W-7Ni-3Fe is used for applications, where the high specific weight of the material plays an important role. They are used as counterweights, rotating inertia members, as well as fur defense purposes(kinetic energy Penetrators, etc.). Because of these applications, it is essential to detemine the dynamic characteristics of tungsten alloy. In this paper, Explicit FEM(finite element method) is employed to investigate the dynamic characteristics of tungsten heavy metal under base of stress wave propagation theory for SHPB, and the model of specimen is divided into two parts to understand the phenomenon that stress wave penetrates through each tungsten base and matrix. This simulation results were compared to experimental one and through this program, the dynamic stress-strain curve of tungsten heavy metal can be obtained using quasi static stress-strain curve of pure tungsten and matrix.
A Study on the Forging of wheel Bearing Hub by using Response Surface Methodology
Song, Yo-Sun ; Yeo, Hong-Tae ; Hur-Kwan-Do ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 100~107
The objective of the study is to improve the quality of wheel bearing hub by the rigid-plastic finite element analysis and the response surface methodology. The rigid-plastic finite element codes, AFDEX-2D and DEFORM-3D, were used to analyze the two-dimensional and three-dimensional forging processes, respectively. The response surface analysis is used to find the minimum underfill by the variation of design variables such as the height of billet after upsetting and punch angles of blocker dies. The metal flow of forged product shows good agreement with the results from 2D and 3D analysis. Also, the quality of the wheel bearing hub has been improved by the optimization of design variables and the machining time has been reduced by the machining allowance.
A Study on the Optimization of a Devided Ball Valve using Characteristic Function
Choi, Jong-Sub ; Park, Young-Chul ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 108~117
In modern industrial society, many kinds of valves have been used to control fluid flow. For the optimization of a ball valve, a quarter of spherical ball was modeled and evaluated. However, there is a difficulty in the application of the optimization technique because of the complexity of the fluid and the restriction of analysis. Therefore, in this study, it is performed to evaluate the stability of an initial model using FEM(Finite Element Method) and CFD. In addition, a shape optimization design of the valve is accomplished using an orthogonal arrangement and characteristic functions. From the result, a new design method is represented that could overcome the time and space restriction in structural design, such as the divided ball valve with less experiment.
Analysis on Kinematic Characteristics for Spatial 3-DOF Parallel Mechanisms Employing Stewart Platform Structure
Lee Seok Hee ; Lee Jung Hun ; Kim Whee Kuk ; Yi Byung Ju ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 118~127
A spatial 3 degrees-of-freedom mechanism employing Stewart Platform structure is proposed: the mechanism maintains the 3- RRPS structure of Stewart Platform but has an additional passive PRR serial sub-chain at the center area of the mechanism in order to constrain the output motion of the mechanism within the output motion space of the added PRR serial subchain. The forward and reverse position analyses of the mechanism are performed. Then the mechanism having both the forward and the reverse closed-form solutions is suggested and its closed form solutions are derived. It is confirmed, through the kinematic analysis of those two proposed mechanisms via kinematic isotropic index, that both the proposed mechanisms have fairly good kinematic characteristics compared to the existing spatial 3-DOF mechanisms in literature.
Experimental Analysis of Bounce, Roll and Pitch Frequencies of Major Systems of a Large Truck using a Multi-axial Road Simulator
Moon, Il-Dong ; Oh, Chae-Youn ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 128~135
This paper presents a scheme for experimentally analyzing bounce, roll and pitch frequencies of major systems of a large truck using a multi-axial road simulator. The excitation input (amplitude and frequency range) fur a frequency response test with the multi-axial road simulator is selected in order that bounce, roll and pitch modes are not coupled each other, the excitation amplitude can be reproduced in a specified excitation frequency range, and tires do not lose contact with posters. Three accelerometers, one gyroscope and four displacement meters are used in the frequency response test using the multi-axial road simulator. The reliability of the presented bounce mode frequency response test scheme is validated by comparing the result from a test using the multi-axial road simulator with the result from a road driving test. The road driving test is performed with velocities of 20km/h and 30km/h, and in an unladen state. The vertical accelerations at the cab and the front axle are measured in the road driving test. The roll and pitch mode frequency response tests are also performed with the presented frequency response test scheme. Roll and pitch frequencies of major systems of a large truck that are hard to acquire from a road driving test are analyzed as well as bounce frequency.
A Study on Motion Constraint of Rotating Spindle in the Parallel Part at the Blocking Plate
Lim Jong Hyun ; Han Geun Jo ; Shim Jae Joon ; Han Dong Seop ; Lee Seong Wook ; Kim Tae Hyung ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 136~142
The function of main starting valve for marine engine is to supply cylinder with the air to start marine engine. But, if the spindle, one of the main starting valve components, doesn't rotate accurately at the designated air pressure, the marine engine may have some trouble in starting. So, to resolve the problem due to spindle .elation in the main starting valve, the blocking device (blocking plate, limit switch, etc.) is installed in the upper part of spindle to constrain the rotation. So, in this paper we introduced the rotation constraining ability of blocking plate prevent the spindle from mis-working in the main starting value of the marine engine.
Coherent Analysis of vehicle HVAC Using the MDSA Method
Oh Jae-Eung ; Hwang DongKun ; Abu Aminudin ; Lee Jung-Youn ; Kim SungSoo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 143~150
To verify applicability of multi-dimensional spectral analysis (MDSA) fur noise source identification two different approaches which are frequency response and coherent function have been investigated. The coherence function approach appears able to separate the correlated system when the noise sources were coherent. In this study, we identify contribution of structure-borne-noise of vehicle HVAC system using MDSA method. Firstly, to identify the applicability of MDSA method, 4-inputs of vehicle HVAC system were the signals measured by accelerometers attached on the selected noise sources which were composed of blower, evaporator, heater and duct. While 1-output which was driver's position sound was the SPL signals measured by a remote microphone, when the blower motor was operating. We identify efficiency of systems modeled with four Inputs/single output through ordinary coherence function (OCF) and partial coherence function (PCF). As a result of experiment, the blower accounted for
of the overall level of sound energy density. Also, according to the analysis of acoustic signal and vibration signals measurement, an investigation of the noise source identification in the vehicle HVAC is presented. With the sound intensity method, the major sources of the vehicle HVAC radiation are verified. Also the method of improving the noise reduction is proposed by attaching damping patch access to blower motor and noise reduction is verified.
A Study on the Dynamic Characteristics of Object Transport System using Ultrasonic Wave
Jeong, Sang-Hwa ; Kim, Hyun-Uk ; Cha, Kyoung-Rae ; Choi, Suk-Bong ; Song, Suk ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 151~158
In the semiconductor and the optical industry, a new transport system which can replace the conventional sliding systems is required. The sliding systems are driven by the magnetic field and conveyer belts. The magnetic field nay damage semiconductor and the contact force may scratch the optical lens. The ultrasonic wave driven system can solve these problems. In this paper, an object transport system using the excitation of ultrasonic wave is proposed. The experiments for finding the optimal progressive frequency and the phase-differences between two ultrasonic wave generators are performed. The relationships between transportation speed and the excitation frequency, flexural beam shapes and amplification voltage are investigated.
Flow Behaviors of Polymers in Micro Hot Embossing Process
Ban Jun Ho ; Shin Jai Ku ; Kim Byeong Hee ; Kim Heon Young ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 159~164
The Hot Embossing Lithography(HEL) as a method fur the fabrication of the nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this paper, we carried out experimental studies and numerical simulations in order to understand the viscous flow of the polymer (PMMA) film during the hot embossing process. To grasp the characteristics of the micro patterning rheology by process parameters (embossing temperature, pressure and time), we have carried out various experiments by using the nickel-coated master fabricated by the deep RIE process and the plasma sputtering. During the hot embossing process, we have observed the characteristics of the viscoelastic behavior of polymer. Also, the viscous flow during the hot embossing process has been simulated by the continuum based FDM(Finite Difference Method) analysis considering the micro effect, such as a surface tension and a contact angle.
Laser-induced chemical vapor deposition of tungsten micro patterns for TFT-LCD circuit repair
Park Jong-Bok ; Kim Chang-Jae ; Park Sang-Hyuck ; Shin Pyung-Eun ; Kang Hyoung-Shik ; Jeong Sung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 165~173
This paper presents the results for deposition of micrometer-scale metal lines on glass for the development of TFT-LCD circuit repair-system. Although there had been a few studies in the late 1980's for the deposition of metallic interconnects by laser-induced chemical vapor deposition, those studies mostly used continuous wave lasers. In this work, a third harmonic Nd:YLF laser (351nm) of high repetition rates, up to 10 KHz, was used as the illumination source and W(CO)s was selected as the precursor. General characteristics of the metal deposit (tungsten) such as height, width, morphology as well as electrical properties were examined for various process conditions. Height of the deposited tungsten lines ranged from 35 to 500 m depending on laser power and scan speed while the width was controlled between 50um using a slit placed in the beam path. The resistivity of the deposited tungsten lines was measured to be below
, which is an acceptable value according to the manufacturing standard. The tungsten lines produced at high scan speed had good surface morphology with little particles around the patterns. Experimental results demonstrated that it is likely that the deposit forms through a hybrid process, namely through the combination of photolytic and pyrolytic mechanisms.
Comparison of Plantar Foot Pressure and Impulse in Various Shoe Types
An Eun-Soo ; EOM Gwang-moon ; Lee Soon-Hyuk ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 174~181
We analyzed the pressure, impulse on 24 sensors location under the foot using the Parolee system. Total 7 kinds of shoes, i.e. sport shoe, high heel shoes (5cm heel, 8cm heel, 13cm heel), platform shoe, inline skate, and heelys were evaluated for 20 normal subjects. Compared with those of sport shoe, greater pressure and impulse were shown on the 1 st phalange and the 1 st metatarsal head and greater impulse on the medial tarsal bone in high-heel shoes. Greater pressure and impulse were shown on medial metatarsal bone and the lateral tarsal bone in platform shoe. Greater impulse was shown on the medial tarsal bone in inline-skate. Heelys shoe showed smaller impulse on the central area of foot. The result of this study is expected to provide useful information about the relationship between the shoe type and the foot pathologies.
Study on enhancing the ultrasonic image for bone densitometry
Shin, Jung-Sik ; Ahn, Jung-Hwan ; Kim, Hyung-Joon ; Kim, Hwa-Young ; Han, Seung-Moo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 182~191
It is very important to obtain a high quality of bone image for an accurate ultrasonic measurement of bone mineral density. In this study, we suggested a technique to acquire an optimal image by adapting an acoustic lens and a properly selected ultrasonic probe. Also, we have applied an image processing algorithm with which automatically makes a decision of brightness and contrast of image by generating threshold level, a composition of ultrasonic data, an elimination of noise using modified median filter, and a real time interpolation. We could confirm much improved resolution of bone image with acoustic lens attached to the ultrasonic probe and with the image processing algorithm suggested in this study. Therefore, it became possible to precisely diagnose the osteoprosis using ultrasonic imaging technique.
Development of the Training System for Equilibrium Sense Using the Unstable Platform
Piao, Yong-Jun ; Yu, Mi ; Kwon, Tae-Kyu ; Hong, Chul-Un ; Kim, Nam-Gyun ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 8, 2005, Pages 192~198
In this paper, we propose a new training system for the improvement of equilibrium sense using unstable platform. The equilibrium sense, which provides orientation with respect to gravity, is important to integrate the vision, somatosensory and vestibular function to maintain the equilibrium sense of the human body. In order to improve the equilibrium sense, we developed the software program such as a block game, pingpong game using Visual C++. These training system for the equilibrium sense consists of unstable platform, computer interface and software program. The unstable platform was a simple structure of elliptical-type which included tilt sensor, wireless RF module and the device of power supply. To evaluate the effect of balance training, we measured and evaluated the parameters as the moving time to the target, duration to maintain cursor in the target of screen and the error between sine curve and acquired data. As a results, the moving time to the target and duration to maintain cursor in the target was improved through the repeating training of equilibrium sense. It was concluded that this system was reliable in the evaluation of equilibrium sense. This system might be applied to clinical use as an effective balance training system.